The present invention concerns a clasp of the type allowing a first and second strand of a watch wristband to be connected.
Clasps for watch wristbands have to answer a certain number of criteria. They have, in particular, to be easy to use, offer total operating security, and be inexpensive to manufacture.
Numerous clasps of the type concerned are known, certain of which answer the aforecited conditions quite well, but have, however, certain drawbacks. Some are for example expensive to manufacture, while others, which are easier to manufacture, are difficult to handle. In this respect, many known clasps are particularly difficult to handle because, in order to assemble or separate the two parts of the clasp, one part has to be pivoted with respect to the other.
Moreover, a large number of known clasps have a shape requiring special manufacturing operations, in particular multiple machining stages, or expensive injection moulds in several parts which increase manufacturing costs.
Such is the case, particularly, of clasps of the unfolding type which, in their simplest embodiment, comprise a basic strip onto which a pivoting strip can be folded down. These strips are attached to each other by one of their ends by means of a hinge, and usually include a snap fitting device allowing one to snapped onto the other in the closed position. In addition to the fact that these unfolding strip clasps have complex shapes which make them difficult and thus expensive to manufacture, they are also often inconvenient to use. Moreover, these systems have the drawback of wearing out quickly and no longer snapping the clasp properly into place after a relatively low number of opening and closing movements. This is essentially due to a high snapping force and, therefore, rapid wear of the system. Further, it frequently occurs that the user inadvertently catches one of the strips of the clasp unintentionally causing it to open, at the risk of losing the watch.
Clasps for open wristbands are also known which allow a first and a second wristband strand to be connected to each other. These clasps conventionally include a buckle and tongue secured using a rod at the free end of one of the strands. The free end of the other strand is passed under the buckle then immobilised by the tongue which penetrates in one of the holes made in said strand. This end can then be slid under a loop which holds it.
Clasps with a buckle have the main advantage of being simple and thus inexpensive to manufacture. However, it frequently occurs that the person wearing the watch lets go of it when he wishes to secure it to his wrist, so that the watch can be damaged by falling. These clasps are also unattractive and consequently increasingly fail to meet the expectations of clients who are looking for watches of more sophisticated design and operation, without however being prepared to sacrifice simplicity of use.
Finally, wristbands which are fastened by means of a clasp with a buckle tend to wear out quickly. This is particularly true for the strand in which the holes intended to receive the tongue are made. Indeed, since a given user always inserts the tongue into the same hole of the wristband, this hole tends to get bigger and to tear. Likewise, a fold is formed at the place where the strand passes under the buckle, such fold also making the wristband fragile and liable to tear.
The object of the present invention is thus to make a wristband clasp for a watch which avoids the aforecited drawbacks, and which is very simple to manufacture and easy and secure to use.
The present invention thus concerns a watch wristband clasp, characterised in that it includes two male and female joining parts able to be, coupled by inserting the male part into the female part, resilient locking means, provided on the male part, locking with catching means provided on the female part when the male part is pushed into an engagement position in said female part, so that it is then impossible to pull the male joining part outwards, the male and female joining parts being able to be uncoupled from each other by pushing the male part further into the female part, so that the locking means are released from the catching means and the male joining part can be pulled out from the female joining part.
As a result of these features, the present invention provides a clasp which is easy to use. Indeed, to fasten the clasp, one need only insert the male joining part into the female joining part as far as the engagement position in which the locking means provided on the male part lock with the catching means provided on the female part. In order to open the clasp, the movement of inserting the male part into the female part is continued. The locking means are then released from the catching means, and the male joining part need only be pulled out of the female joining part.
The clasp according to the invention also offers good working reliability. When the male part is pushed into the female part as far as the engagement position, it is impossible to pull said male part out of said female part. Consequently, even if the user inadvertently catches one of the parts of the clasp, it will not open. The clasp will only open if the user intentionally acts on said clasp by pushing the male part further into the female part.
According to a complementary feature of the invention, the locking means are resilient transversely to the direction of engagement of the male joining part in the female joining part, and are resilient in a plane perpendicular to the plane of the clasp.
When the male joining part is inserted in the female joining part, the catching means provided on the female part force the locking means of the male joining part back transversely to the direction of engagement of the male part in the female part in order to deform these locking means resiliently and to put them under tension. The resilient locking means then lock abruptly with the catching means, assuring a secure coupling which prevents any accidental separation. Consequently, when one wishes to open the clasp and the male part is pushed further into the female part, the locking means are deformed resiliently downwards in a direction perpendicular to the plane of the clasp, then they return to their initial shape via the forces of resilience to escape the catching means. The male joining part can then be easily removed from the female joining part.
The clasp according to the invention does not require any setting or adjustment. It also does not include any moving part to release the two coupled joining parts, which allows manufacturing costs to be substantially reduced. Finally, the male and female joining parts can be fitted together quickly and with the greatest of ease, and can be held securely assembled so as to prevent any accidental separation.